On Oct 21 '15 18:58, Jarkko Sakkinen wrote: > On Tue, Oct 20, 2015 at 05:58:35PM +0300, Jarkko Sakkinen wrote: > > On Tue, Oct 20, 2015 at 01:49:02PM +0200, Andreas Ziegler wrote: > > > Hi Jarkko, > > > > > > your patch "tpm, tpm_tis: fix tpm_tis ACPI detection issue with TPM 2.0" > > > showed up as commit 399235dc6e95 in linux-next today (that is, > > > next-20151020). I noticed it because we (a research group from > > > Erlangen[0]) are running daily checks on linux-next. > > > > > > Your commit creates the following structure of #ifdef blocks in > > > drivers/char/tpm/tpm_tis.c following line 1088: > > > > > > #ifdef CONFIG_ACPI > > > ... > > > #ifdef CONFIG_PNP > > > ... > > > #endif > > > ... > > > #endif > > > > > > Looking at the definition of CONFIG_ACPI at drivers/acpi/Kconfig, line > > > 5, we see that ACPI unconditionally selects PNP, meaning that CONFIG_PNP > > > is always enabled if CONFIG_ACPI has been enabled. > > > Thus, the inner #ifdef statement can never evaluate to 'false' if the > > > outer #ifdef evaluates to true (i.e., CONFIG_ACPI is enabled), and > > > hence, the #ifdef is unnecessary. > > > > > > The same situation holds for the nested structure following line 1124, > > > where the #ifdef CONFIG_PNP at line 1129 is unnecessary. > > > > > > Is this correct or did we miss something? > > > > Good catch. Shoud I send a separate fix for this? Thanks for pointing > > this out. > > In all I would cases do a separate fix and do not fixup the original > patchs because I wouldn't consider this a regression. > > The next question is: will it always be like this? Can I safely assume > that ACPI will always select PNP unconditionally? This is so minor > cosmetic glitch in the code that I'm getting second thoughts whether I > should anything to this or not.
Any option has certain benefits. In the current form, a reader might (falsely) assume that the block is configurable. However, if the constraints of ACPI or PNP change, the situation might look different. Best regards, Valentin -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
